Peak and submaximal steady-state metabolic and cardiorespiratory responses during arm-powered and arm-trunk-powered handbike ergometry in able-bodied participants

Handbike configurations and the prevalence of experienced sitting and riding-related problems in recreational handcyclists training for the HandbikeBattle

Implications for rehabilitationA large variety in handbike configurations is seen in recreationally-active handcyclists.Although the majority of the recreationally-active handcyclists seemed to be satisfied with their handbike configurations, 31-50% of them thought that their handbike configuration could be improved.Evidence-based guidelines for handbike fitting should be developed in the future.

Steering Does Affect Biophysical Responses in Asynchronous, but Not Synchronous Submaximal Handcycle Ergometry in Able-Bodied Men

Real-life daily handcycling requires combined propulsion and steering to control the front wheel. Today, the handcycle cranks are mostly mounted synchronously unlike the early handcycle generations. Alternatively, arm cycle ergometers do not require steering and the cranks are mostly positioned asynchronously. The current study aims to evaluate the effects of combining propulsion and steering requirements on synchronous and asynchronous submaximal handcycle ergometry. We hypothesize that asynchronous handcycling with steering results in the mechanically least efficient condition, due to compensation for unwanted rotations that are not seen in synchronous handcycling, regardless of steering. Sixteen able-bodied male novices volunteered in this lab-based experiment. The set-up consisted of a handcycle ergometer with 3D force sensors at each crank that also allows “natural” steering. Four submaximal steady-state (60 rpm, ~35 W) exercise conditions were presented in a counterbalanced order: synchronous with a fixed steering axis, synchronous with steering, asynchronous with a fixed axis and asynchronous with steering. All participants practiced 3 × 4 mins with 30 mins rest in between every condition. Finally, they did handcycle for 4 mins in each of the four conditions, interspaced with 10 mins rest, while metabolic outcomes, kinetics and kinematics of the ergometer were recorded. The additional steering component did not influence velocity, torque and power production during synchronous handcycling and therefore resulted in an equal metabolically efficient handcycling configuration compared to the fixed condition. Contrarily, asynchronous handcycling with steering requirements showed a reduced mechanical efficiency, as velocity around the steering axis increased and torque and power production were less effective. Based on the torque production around the crank and steering axes, neuromuscular compensation strategies seem necessary to prevent steering movements in the asynchronous mode. To practice or test real-life daily synchronous handcycling, a synchronous crank set-up of the ergometer is advised, as exercise performance in terms of mechanical efficiency, metabolic strain, and torque production is independent of steering requirements in that mode. Asynchronous handcycling or arm ergometry demands a different handcycle technique in terms of torque production and results in higher metabolic responses than synchronous handcycling, making it unsuitable for testing.

A Role for Trunk Function in Elite Recumbent Handcycling Performance?

Handcycling classification considers trunk function, but there is limited scientific evidence of trunk involvement in recumbent performance. This study investigated the association between trunk function and recumbent handcycling performance of athletes without upper-limb impairments (H3-H4 sport classes). The study was divided into two parts. First, 528 time-trial results from 81 handcyclists with spinal cord injury (SCI) were obtained between 2014 and 2020. Average time-trial velocity was used as performance measure and SCI level as trunk function determinant. Multilevel regression analysis was performed to analyse differences in performance among SCI groups while correcting for lesion completeness, sex, and age. Second, in 26 handcyclists, standardised trunk flexion strength was measured with a handheld dynamometer. Peak and mean power-output from a sprint test and time-trial average velocity were used as performance measures. Spearman correlations were conducted to investigate the association between trunk strength and performance. Results showed that the different SCI groups did not exhibit significant differences in performance. Furthermore, trunk flexion strength and performance exhibited non-significant weak to moderate correlations (for time-trial speed: rs = 0.36; p = 0.07). Results of both analyses suggest that trunk flexion strength does not seem to significantly impact recumbent handcycling performance in athletes without upper-limb impairments.

Bioenergetics and Biomechanics of Handcycling at Submaximal Speeds in Athletes with a Spinal Cord Injury

BACKGROUND

A study aimed at comparing bioenergetics and biomechanical parameters between athletes with tetraplegia and paraplegia riding race handbikes at submaximal speeds in ecological conditions.

METHODS

Five athletes with tetraplegia (C6-T1, 43 ± 6 yrs, 63 ± 14 kg) and 12 athletes with paraplegia (T4-S5, 44 ± 7 yrs, 72 ± 12 kg) rode their handbikes at submaximal speeds under metabolic measurements. A deceleration method (coasting down) was applied to calculate the rolling resistance and frontal picture of each participant was taken to calculate air resistance. The net overall Mechanical Efficiency (Eff) was calculated by dividing external mechanical work to the corresponding Metabolic Power.

RESULTS

Athletes with tetraplegia reached a lower aerobic speed (4.7 ± 0.6 m s^-1 vs. 7.1 ± 0.9 m s^-1, P = 0.001) and Mechanical Power (54 ± 15 W vs. 111 ± 25 W, P = 0.001) compared with athletes with paraplegia. The metabolic cost was around 1 J kg^-1 m^-1 for both groups. The Eff values (17 ± 2% vs. 19 ± 3%, P = 0.262) suggested that the handbike is an efficient assisted locomotion device.

CONCLUSION

Handbikers with tetraplegia showed lower aerobic performances but a similar metabolic cost compared with handbikers with paraplegia at submaximal speeds in ecological conditions.

Crank fore-aft position alters the distribution of work over the push and pull phase during synchronous recumbent handcycling of able-bodied participants

Objective

The objective of the current study was to investigate the effect of four different crank fore-aft positions on elbow flexion and shoulder protraction, the consequent propulsion kinetics and the physiological responses during handcycling.

Methods

Twelve able-bodied male participants volunteered in this study. Crank fore-aft positions were standardised at 94%, 97%, 100% and 103% of the participants’ arm length. Two submaximal 3 min trials were performed at a fixed cadence (70 rpm), in a recumbent handcyle attached to an ergometer at two fixed power outputs (30W and 60W). Elbow flexion, shoulder protraction, propulsion kinetics and physiological responses of the participants were continuously measured.

Results

As crank fore-aft distance increased, a decrease in elbow flexion (42±4, 37±3, 33±3, 29±3°) and an increase shoulder protraction was observed (29±5, 31±5, 34±5, 36±5°). The percentage of work done in the pull phase increased as well (62±7, 65±7, 67±6, 69±8%, at 60W), which was in line with an increased peak torque during the pull phase (8.8±1.6, 9.0±1.4, 9.4±1.5, 9.7±1.4Nm, at 60W) and reduced peak torque during the push phase (6.0±0.9, 5.6±0.9,5.6±0.9, 5.4±1.0Nm, in 60W condition). Despite these changes in work distribution, there were no significant changes in gross mechanical efficiency (15.7±0.8, 16.2±1.1, 15.8±0.9, 15.6±1.0%, at 60W). The same patterns were observed in the 30W condition.

Conclusions

From a biomechanical perspective the crank position closest to the trunk (94%) seems to be advantageous, because it evens the load over the push and pull phase, which reduces speed fluctuations, without causing an increase in whole body energy expenditure and hence a decrease of gross mechanical efficiency. These findings may help handcyclists to optimize their recumbent handcycle configuration.

Sitting position affects performance in cross-country sit-skiing

PURPOSE

In cross-country sit-skiing (XCSS), athletes with reduced trunk control predominantly sit with the knees higher than the hips (KH); a position often associated with large spinal flexion. Therefore, to improve spinal curvature a new sledge with frontal trunk support, where knees are lower than hips (KL) was created. It was hypothesized that the KL position would improve respiratory function and enhance performance in seated double-poling compared to KH.

METHODS

Ten female able-bodied cross-country skiers (age 25.5 ± 3.8 years, height 1.65 ± 0.05 m, mass 61.1 ± 6.8 kg) completed a 30 s all-out test (WIN), a submaximal incremental test including 3-7 3 min loads (SUB) and a maximal 3 min time trial (MAX) in both KL and KH positions. During SUB and MAX external power, pole forces, surface electromyography, and kinematics were measured. Metabolic rates were calculated from oxygen consumption and blood lactate concentrations.

RESULTS

KL reduced spinal flexion and range of motion at the hip joint and indicated more muscle activation in the triceps. Performance (W kg−1) was impeded in both WIN (KH 1.40 ± 0.30 vs. KL 1.13 ± 0.33, p < 0.01) and MAX (KH 0.88 ± 0.19 vs. KL 0.67 ± 0.14, p < 0.01). KH resulted in lower lactate concentration, anaerobic metabolic rate, and minute ventilation for equal power output [corrected].

CONCLUSIONS

The new KL position can be recommended due to improved respiratory function but may impede performance. Generalization of results to XCSS athletes with reduced trunk muscle control may be limited, but these results can serve as a control for future studies of para-athletes.

Gender differences in power production, energetic capacity and efficiency of elite cross‑country skiers during whole‑body, upper‑body, and arm poling

PURPOSE

To characterize gender differences in power output, energetic capacity and exercise efficiency during whole-body (WP), upper-body (UP), and arm poling (AP).

METHODS

Ten male and ten female elite cross-country skiers, matched for international performance level, completed three incremental submaximal tests and a 3-min self-paced performance test on a Concept2 SkiErg. Power output, cardiorespiratory and kinematic variables were monitored. Body composition was determined by dual-energy X-ray absorptiometry.

RESULTS

The men demonstrated 87, 97 and 103% higher power output, and 51, 65 and 71% higher VO2peak (L min(−1)) than the women during WP, UP and AP, respectively, while utilizing ~10% more of their running VO2max in all modes (all P < 0.001). The men had 35, 38 and 59% more lean mass in the whole body, upper body and arms (all P < 0.001). The men exhibited greater shoulder and elbow extension at the start of poling and greater trunk flexion at the end of poling (all P < 0.05). The relationship between VO2 and power output did not differ between the men and women.

CONCLUSIONS

Gender differences in power production and peak aerobic capacity increased sequentially from WP to UP to AP, coinciding with a greater portion of the muscle mass in the arms of the men. Although the men and women employed each poling technique differently, the estimated efficiency of double poling was independent of gender.

Influence of noncircular chainring on male physiological parameters in hand cycling

The purpose of this study was to examine the influence of a noncircular chainring (NCC) compared with a conventional circular chainring (CC) on hand cycling performance. Eleven nondisabled male participants with no hand cycling experience initially completed an incremental exercise test. Afterward, the participants completed two 20 s sprint tests, followed by a 20 min endurance test and then another two 20 s sprint tests. An NCC and a CC were used in random order on two separate occasions. To compare the effects of the NCC and CC on power data of the sprint tests and metabolic response during the endurance test, a two-way analysis of variance for repeated measures was used. Average power values of the sprint tests showed no significant difference between NCC and CC, but over time, values of the first and third sprint tests were higher than those of the second and fourth sprint tests for both chainrings. Values of energy expenditure (kilojoules), gross efficiency (percentage), and net efficiency (percentage) after 10 and 20 min during the endurance test using NCC and CC showed no significant differences (p > 0.05) either between tests or over time. Under the current test conditions and focusing on physiological parameters, a performance optimization using an NCC in hand cycling could not be proven.